Used tires and rubber from used tires are being generated as waste in ever-increasing quantities. The use of these waste materials is frequently problematic. A primary use is for energy recovery, for example by burning in cement manufacture. However, in particular as the result of regulatory restrictions, recycling is increasingly being required. It is known that granules, i.e. powders or meals, may be produced from used tires. The granules may be used, for example, as filler in the rubber industry. However, it is also known to produce molded parts and mats, i.e. sports surfaces and safety mats, from such rubber granules in molding presses.
A method is known from DE 30 17 899, for example, of making PUR-bound rubber granule mats, where rubber granules from used tires, for example as the main component, and a polyurethane-based binder, catalyst, and other auxiliary materials and additives are deformed under pressure and heat in a continuous press. Conveyor belt speeds of 6 to 8 m per minute, pressures of 1 to 3 bar, and temperatures of 120 to 140° C. are selected. When the mat-forming mixture enters the belt molding machine, steam may be blown in to accelerate curing.
A disadvantage of the known methods of making rubber sheets, rubber mats, or the like from rubber granules from used tires is that very long press cycles are frequently necessary. This is due to the very poor thermal conductivity of rubber. Heating time factors for sheet rubber materials are typically 60 sec per mm of product thickness. For thicker products, heat-through times of several hours are necessary. For this reason the manufacture of various products from rubber granules from used tires is often uneconomical. These problems are addressed by the invention.